Enclosure for pad mounted electrical switchgear having sliding top and end panels

ABSTRACT

Metallic housing for pad-mounted high voltage switches and fuses has sliding top panel which must be shifted forward or back to permit removal of back and front sliding access panels. A lock prevents movement of the top panel from overlying relation to the front and rear panels. Fuses are mounted in a drawer which is locked closed and can only be opened when the lock under the top panel is uncovered. Access to the manual operator for the switch assembly or assemblies is accessible only when the top panel is shifted back. A mechanical maze construction between exposed movable panels reduces likelihood of entrance of wire and the like.

United States Patent Emmett R. Beebe Glenview, Ill.

Sept. 16,1969

Apr. 6, 197 1 S 8: C Electric Company Chicago, Ill.

Inventor Appl. No. Filed Patented Assignee ENCLOSURE FOR PAD MOUNTED ELECTRICAL SWITCHGEAR HAVING SLIDING TOP AND END PANELS Primary Examiner-E. A. Goldberg Assistant Examiner-Gerald P. Tolin Attorney-Robert R. Lockwood ABSTRACT: Metallic housing for pad-mounted high voltage switches and fuses has sliding top panel which must be shifted forward or back to permit removal of back and from sliding access panels. A lock prevents movement of the. top panel from overlying relation to the front and rear panels. Fuses are mounted in a drawer which is locked closed and can only be opened when the lock under the top panel is uncovered. Access to the manual operator for the switch assembly or assemblies is accessible only when the top panel is shifted back. A mechanical maze construction between exposed movable panels reduces likelihood of entrance of wire and the like.

Patented April 6, 197

5 Sheets-Sheet 1 lllillll I Patent ed April 6, 1971 5 Sheets-Sheet l Patented April 6, 1971 3,573561 5 Sheets-Sheet 3 Patented A ril 6, 1971 3,573,561

5 Sheets-Sheet 4 Patented April 6, 1971 3,573,561

5 Sheets-Sheet 5 ENCLOSURE FOR PAD MOUNTED ELECTRICAL SWITCIIGEAR HAVING SLIDING TOP AND END PANELS This invention is an improvement over the construction disclosed in Hamer et al., U.S. Pat. No. 3,339,118, issued Aug. 29, 1967.

Electrical equipment enclosures exposed to the general public must have maximum resistance to tampering or to an unknowledgeable person poking a wire into it. The construction disclosed herein minimizes exposed hardware, locks etc., and all separable joints are of a mechanical maze design which effectively defeats entrance with a wire.

Among the objects of this invention are: To provide for enclosing high voltage electrical switchgear in a new and improved manner; for this purpose to provide a metal enclosure having a sliding top panel in closed position overlying front and rear sliding panels and are venting their removal until the top panel is slid either back or forward; to construct the metal enclosure with a mechanical maze in such a manner as'to 0bstruct the insertion of metallic objects, such as wire, into contact with internal electrical switchgear to lock the top panel in closed position; to locate switchgear operating means and viewing windows under the sliding top panel where access can be had only when the top panel is moved back or rearwardly; to prevent operation of the lock except when the top panel is closed or centered overlying both front and rear sliding panels; to limit sliding movement of the top panel in either direction; to reduce the friction incident to movement of the top panel; to guide the front and rear panels to their closed positions; to mount fuses in a drawer which-can be withdrawn from the front of the enclosure; and to secure the drawer closed by a lock to which access can be had only when the top panel is moved back or rearwardly.

According to this invention a support frame is provided for mounting disconnecting switch and fuse devices within a metallic enclosure that is adapted to be positioned on a concrete pad for use in distributing electric power at voltages of the order of KV. The system may be single phase or three phase. The enclosure has stationary metallic sidewalls, a horizontally slidable metallic top panel, and front and rear vertically slidable end panels. One or more fuses are mounted in a drawer which is horizontally slidable through the front side of the enclosure. When the top panel is in closed position, it overlies the front and rear panels and thus prevents their removal. On rearward movement of the top panel, the front panel or panels can be lifted to permit access to the interior'of the enclosure. Likewise, on forward movement of the top panel, the rear panel or panels can be lifted to permit access to the rear part of the enclosure where cable terminals are located. Stops limit the sliding movement of the top panel which is facilitated by antifriction bearings. A lock prevents movement of the top panel from its closed position. The lock can be applied only in this position. The front and rear panels are guided to their fully closed positions by guides on the support frame having inclined surfaces. The panels are limited in their downward movement by stops on the support frame at the upper ends of the panels. The drawer is locked to the support frame in the closed position. Access to the drawer lock can be obtained only when the top panel has been moved rearwardly.

In the drawings:

FIG. 1 is a perspective view of a single phase metal enclosed switchgear;

FIG. 2 is a view, similar to FIG. 1, showing certain details of the switchgear within the metal enclosure and various parts shown in different operating positions;

FIG. 3 is a perspective view, at a reduced scale, of the metal enclosed switchgear shown in FIG. 1, the view being taken looking generally from the rear;

FIG. 4 shows diagrammatically the circuit connections involved in the single phase switchgear;

FIG. 5 is a perspective view of a metal enclosure for three phase pad mounted switchgear;

FIG. 6 is a view, similar to FIG. 5, showing certain of the details of the polyphase switchgear within the metallic housing as shown in FIG. 5;

FIG. 7, sheet 2, is a perspective view, at a reduced scale, of the metal enclosed switchgear, this view being taken looking from the rear:

FIG. 8 shows diagrammatically the circuit connections for the three phase switchgear;

FIG. 9 is perspective view, similar to FIG. 6, and shows certain details of construction of the metal enclosure;

FIG. 10 is a vertical sectional view taken generally along line 10-10 of FIG. 9;

FIG. 11 is a horizontal sectional view, of an enlarged scale, taken generally along line 11-11 of FIG. 10;

FIG. 11A is fragmentary perspective view of the guide member and its mounting as shown in FIG. 10;

FIG. 12 is a vertical sectional view taken generally along line 12-12 of FIG. 9;

FIG. 113, sheet 4, is a vertical sectional view taken generally along line 13-13 of FIG. 12;

FIG. 14, sheet 4, is a vertical sectional view taken generally along line 14-14 of FIG. 13;

FIG. 15 is an elevational view taken generally along line 15-15 of FIG. 9;

FIG. 16 is a vertical sectional view taken generally along line 16-16 of FIG. 15.

FIG. 17 is a vertical sectional view taken generally along line 17-17 of FIG. 16;

FIG. 18 is a vertical sectional view taken generally along line 18-18 through a portion of the fuse drawer shown in FIG. 9 to illustrate the arrangement of the fuse drawer locking means; and

FIG. 19 shows an alternate position of the hasp for the locking means shown in FIG. 18.

In FIGS. 1, 2 and 3 the reference character 10 designates, generally, a metallic housing for single phase electrical switchgear adapted to be mounted on a concrete pad. It provides a support structure for the enclosed switchgear. The housing 10 includes metallic sidewalls l1 and 12 between which a fuse drawer, shown generally at 13, is slidably mounted along the bottom portion. The fuse drawer 13 includes a metallic fuse panel 14 having an insulator 15 extending from its rear side on which a fuse 16 is mounted at one end. At its other end the fuse 16 has a terminal 17 for insertion in a plug-in contact that is carried by an insulator 19 which extends forwardly from a rear inner wall 20 of the metallic housing 10. A cable terminator 21 extends from the insulator 19 through which a terminal rod extends for connection to one side of a single phase loop feeder circuit. A lock 23 is mounted on the metallic fuse panel 14 for locking the fuse drawer 14 to the metallic housing 10 against opening movement. When the lock 23 is unlocked, the fuse drawer 13 can be opened in the direction indicated by arrow 24.

Connection to the fuse 16 is provided by a contact arm 25 that extends radially and rearwardly from the end of the fuse 16 mounted on the insulator 15 for engagement with a switch blade support plate 26 from which a switch blade 27 extends. The switch blade 27 is arranged to be pivoted into and out of an arc chute 28 which is mounted on a stationary switch terminal 29 that is carried by an insulator 30 which extends forwardly from the rear inner wall 20. A cable terminator 31, connected to a terminal rod within the insulator 30, provides for connection to the other side of the feeder circuit. The switch blade 27 and support plate 26 are mounted for pivotal movement with an insulator 32 about a horizontal axis. The insulator 32 and parts mounted thereon are arranged to be pivoted by a spring operator, indicated generally at 33, constructed as disclosed in a copending application of Bematt and Gelfand. The spring operator 33 is arranged to be manually operated through the agency of a manual tool-receiving shaft 34 which is accessible at the top and near the front end of the metallic housing 10.

A rectangular frame 37 is mounted on the metallic housing around a front opening 38 which provides access to the switch comprising the switch blade 27, stationary switch terminal 29 and parts associated therewith. A metallic front panel 39 is slidably mounted on the sides of the rectangular frame 37 for closing the front opening 38.

The upper end of the metallic housing 10 is closed by a metallic top panel 40 which is slidable endwise thereof through limited distances. Its front end 41 overlies the upper end of the manual tool-receiving shaft 34 and also the metallic front panel 39. Access to the former and removal of the latter are prevented as long as the top panel 40 remains in the position shown in FIG. 1. Locks, shown generally at 42 and 43, in the sidewalls 11 and 12 are arranged to hold the top panel 40 in the position shown in FIG. 1. They can be unlocked only by authorized personnel.

In FIG. 3 a rectangular frame 44 at the rear end of the metallic housing 10 surrounds a rear opening 45 through which access can be had to the cable terminators 21 and 31. A metallic rear panel 46 is slidably mounted on the rectangular frame 44 for closing the rear opening 45. When the top panel 40 is in the position shown in FIG. l, it overlies both the front panel 39 and the rear panel 46, thereby preventing removal thereof. When the top panel 40 is moved rearwardly in the direction indicated by arrow 47 in FIG. 2, access then can be had to the manual tool-receiving shaft 34 and the front panel 39 can be moved upwardly as indicated by arrow 48 to provide access to the front opening 38. The rear end 49 of the top panel 40 overlies the rear panel 46. When the top panel 40 is moved forwardly as indicated by arrow 50 in FIG. 3, the rear end 49 no longer overlies the rear panel 46 and it can be moved upwardly as indicated by arrow 51. FIG. 4 shows diagrammatically the circuit connections employed for the electrical switchgear within the metallic housing 10.

The manner in which the panels 39, 40 and 46 are slidably mounted on the metallic housing 10 and the construction of the locks 42 and 43 will be described in detail hereinafter in connection with the disclosure of a three phase system arranged for connection in a loop feeder circuit. Insofar as possible the same reference characters will be employed for corresponding parts of the three phase system as are employed for the single phase system illustrated in FIGS. 1-4.

In FIGS. 5, 6 and 7 a metallic housing and frame structure is indicated, generally, at 52 for enclosing a three phase fuse and switch loop feeder system. The housing 52 includes metallic sidewalls 53 and 54 having metallic front panels 55 and 56.

vertically slidably mounted thereon. FIG. 9 shows how the panels 55 and 56 are mounted on rectangular frames one of which is indicated at 58. The frames surround front openings one of which is indicated at 60 which provide access to the interior of the metallic housing 52. Between the front panels 55 and 56 a fuse drawer, indicated at 61, is mounted for horizontal sliding movement. It includes a metallic fuse panel 62, corresponding to the metallic fuse panel 14 previously described. The fuse panel 62, as shown in FIG. 6, carries three insulators that extend rearwardly and each of them has a fuse 16 mounted at its inner end provided with a terminal 17 at the opposite end for engagement with plug-in contacts 18 that are carried by insulators 19 which extend forwardly from a rear inner wall 63. As shown in FIG. 7, cable tenninators 21 provide connections to a three phase load circuit. A lock, shown generally at 64 in FIG. 9, is employed for holding the fuse drawer 61 in closed position.

The upper end of the metallic housing 52 is closed by a slidable metallic top panel 65 the front end 66 of which in the closed position overlies the front panels 55 and 56, the lock 64 and the manual tool-receiving shafts 34 for the spring operators 33. Locks 42 and 43 in their locked positions prevent movement of the top panel 65 in either direction until they are unlocked by authorized personnel.

The rear end of the metallic housing 52 is closed by metallic rear panels 67, 68 and 69, FIG. 7, which are slidably mounted in a manner to be described. The rear end 70 of the top panel 65 overlies the rear panels 67, 68 and 69 in their normal closed positions and must he slid forwardly in order to permit removal of the rear panels for access to the cable terminators 21 within the metallic housing 52.

In FIG. 6 metallic support frames, shown generally at 74 and 75 are positioned within the metallic housing 10 on opposite sides of the fuse drawer 61. They carry three phase switch assemblies, indicated generally at 76 and 77 respective ly, which are generally similar to the single phase switch assembly shown in FIG. 2. The switch blades 27 are mounted on stacks of insulators 32 and are arranged to be pivoted by spring operators 33 operated by manual tool-receiving shafts 34. The switch blades 27 extend from switch blade support plates 26 that are arranged to be contacted by contact arms 25 from the respective fuses 16. FIG. 8 shows the circuit connections diagrammatically.

FIGS. 9, 15, 16 and 17 show in more detail the construction of the locks 42 and 43 and the manner in which they cooperate with the slidable top panel 65 to hold it in the locked position. For example, the lock 42 which is identical with the lock 43, comprises a hasp 81 that is pivotally mounted at 82 at the lower end of a bottom wall 83 of a recess 84 in the sidewall 53. The hasp 81 is generally J-shaped and at its distal end it has slot 85 that is arranged to receive a shackle receiving staple 86 that is secured to the upper end of the bottom wall 83. The staple 86 is in the form of a flat plate and is provided with an opening 87 for receiving a shackle 88 of a padlock 89. It will be observed in FIG. 9 that the slot 85 is located in a hook portion 90 of the hasp 81 and that this portion includes a depending wall 91 which overlies the shackle 88 and thus prevents access to the padlock 89.

As shown in FIG. 16, an opening 94 is provided in the bottom wall 83 to receive a locking tongue 95 which is secured to and extends rearwardly from the hasp 81. The locking tongue 95 extends into locking engagement with the top panel 65 through an opening 96 in a head portion 97 that forms a part of a T-shaped locking member 98 which is secured by bolts 99 to the underside of the top panel 65. A cover 96 overlies the opening 96 in the head portion 97 to prevent access to the interior of the metallic housing 52 through the opening 96. When the top panel 65 is moved rearwardly or toward the left, FIG. 17, the right end 100 of the head portion 97 overlies the opening 94 in the bottom wall 83 and thus prevents movement of the hasp 81 to the locked position. When the panel 65 is moved forwardly or toward the right, the left end 101 of the head portion 97 overlies the opening 94 and again prevents movement of the hasp 81 to the locked position. Thus the locks 42 and 43 cannot be locked except when the top panel 65 is in the central position where the opening 94 registers with the opening 96 to permit insertion of the locking tongue 95.

FIGS. 18 and 19 show the arrangement of the lock 64 for the fuse drawer 61 which is accessible only when the top panel 65 is moved rearwardly to the position shown in FIG. 9. The hasp 81 is pivoted at 102 near the upper end of the fuse panel 62 and the slot 85 therein is arranged to receive a shacklereceiving staple 103 which extends upwardly from a front frame member 104 of the metallic housing 52. The wall 91 overlies the shackle 88 and thus prevents access to the padlock 89.

FIGS. 12, 13 and 14 show the arrangement of antifriction assemblies 107 for facilitating the sliding movement of the top panel 65. Preferably three of the assemblies 107 are employed along each side of the top panel 65. They are generally identical in construction. Each includes a support bar 108 that is carried by an angle member 109 which is secured by bolts 110 to an intumed flange 111 of the sidewall 54. A ball 112 rolls along the top side of the support bar 108 and engages the underside of the top panel 65.

Provision is made for limiting the forward and rearward movements of the top panel 65. For this purpose the top panel 65 has down turned end flanges 113 and 114, FIG. 12, from the lower edges of which inturned edge portions 115 and 116 extend. They comprise stop means and are arranged to engage an upstanding flange "7 carried by a rear frame member 118 and an upstanding flange 119 which fonns a part of the front frame member 104. The broken line positions of the end flanges 113 and 114 indicate the limits of extent of forward and rearward movement of the top panel 65.

H65. 10 and 11 illustrate the manner in which the rear panel 69 is slidably mounted on the housing 52. This is typical for the front panels 55 and 56 and the other two rear panels 67 and 68. The panel 69 isarranged to close off an opening 121 through which access may be had to the interior of the housing 52. The panel 69, FIG. 11 has a rearwardly extended flange 122 along each side having an inturned edge 123 the lower end 124 of which is arranged in the downward movement of the panel 69 to engage an inclined surface 125 on a guide member 126 secured by a flat head screw 126' to an outwardly turned flange 127 from the sidewall 53. As the lower end 124 of the intumed edge portion 123 engages the inclined surface 125 of the guide member 126, the inner surface of the panel 69 is moved into engagement with a forward face 128 of the guide member 126. At its upper end panel 69 has an intumed flange 129 and a down turned edge portion 130. This forms a pocket for a guide member 131 which has a slot 132 in it for receiving an upturned flange 133 of the rear frame member 118.

Windows 134, FIG. 9, in the front frame member 104, provide for inspection of thethree phase switch assemblies 76 and 77 without requiring removal of the front panels 55 and 56.

Only when the top panel 65 is moved rearwardly to the position shown in FIG. 9 is it possible to have access to the fuse drawer lock 64 and to the manual tool-receiving shafts 34 for operating the switch assemblies 76 and 77. When the top panel 65 is moved rearwardly, as shown in H6. 9, access can be had to the padlock 89 or the lock 64. The lock 64 can be unlocked and the fuse drawer 6] opened. Also, in this position of the top panel 65 a suitable tool or wrench can be inserted in the upper ends of the shafts 34 for operating the switch assemblies 76 and 77. With the top panel 65 moved rearwardly after unlocking of the locks 42 and 43, the front panels 55 and 56 can be slid upwardly to permit access to the switch assemblies 76 and 77. On movement of the top panel 65 forwardly to the position shown in FIG. 7, the rear end 70 of the top panel 65 uncovers the upper ends of the rear panels 67, 68 and 69. They can be slid upwardly to provide access to the cable terminators 21 and 31. In either the rear or forward positions of the top panel 65, the hasps 81 of the locks 42 and 43 cannot be returned to the locked position since either the end 100 or the end 101 of the head portion 97 of the locking member 98 overlies the opening 94 in the bottom wall 83 of the recess 84 in the respective sidewall 53 or 54.

A mechanical maze construction is provided along the edges of the top panel 69 and along the edges of the front panels 55 and 56 and of the rear panels 67, 68 and 69. This construction reduces the likelihood that a tool or wire having a small cross section can be inserted into the interior of the metallic housing 52 where contact might be made with a part of the switchgear energized at a high voltage. FIGS. 10, ll, 12 and 16 are typical illustrations of the mechanical maze construction. For example in F 1G. 10, the end panel 69 has the intumed flange 129 that terminates in the down turned edge portion 130 and defines a pocket, not only for the guide member 131 but also for receiving the upturned flange 133 from the rear frame member 118 which, with the adjacent flange sections 138 and 139 also define a pocket.

lclaim:

1. In combination:

electrical switchgear;

overlying said end panels thereby preventing opening thereof until it IS slid in one direction to uncover one en panel and in the opposite direction to uncover the other end panel.

2. The combination according to claim 1 wherein stop means on said enclosure limit sliding movement of said top panel in opposite directions.

3. The combination according to claim 2 wherein locking means on said enclosure prevent movement of said top panel in either direction from said closed position.

4. The combination according to claim 3 wherein said locking means includes:

an inverted T-shaped locking bar depending inside said enclosure from said top panel and having an opening intermediate the ends of its crossbar portion registering with an opening in a sidewall of said enclosure when said top panel occupies its closed position; and

a locking member pivoted on said sidewall and having a tongue for extending through said registering openings; and

the parts of said crossbar portion at the ends of said opening therein overlying said opening in said sidewall when said top panel is moved away from its closed position thereby preventing insertion of said tongue in said opening in said crossbar portion.

5. The combination according to claim 1 wherein:

a drawer is slidably mounted on said enclosure for movement out of one end thereof and carries part of said switchgear; and

locking means on said enclosure prevent withdrawal of said drawer.

6. The combination according to claim 5 wherein said locking means underlies said top panel in its closed position and is accessible only when said top panel is moved in one direction away from its closed position.

7. The combination according to claim 1 wherein:

an outstanding flange borders said opening at each end; and

guide means at the lower end of each of said openings hold the respective end panel against the respective flange.

8. The combination according to claim 7 wherein said guide means has an inclined surface for engaging the lower end of a vertical flange along the respective side of each end panel.

9. The combination according to claim 7 wherein stop means at the top of each end panel engage the respective flange and limit the extent of downward travel thereof.

10. The combination according to claim 1 wherein antifriction means along the upper edges of the sidewalls of said enclosure support said top panel and facilitate sliding movement thereof.

11. The combination according to claim 10 wherein each 'antifriction means includes:

a support bar carried by the respective sidewall of said enclosure; and a ball on said support bar engaging the underside of said top panel. 12. The combination according to claim 1 wherein a mechanical maze construction is located along the edges of said panels to reduce the likelihood of entrance into said enclosure of small cross section, tools, wire and the like.

13. The combination according to claim 12 wherein said mechanical maze comprises interfitting flange means on said panels and said enclosure. 

1. In combination: electrical switchgear; an enclosure for said switchgear having an opening at each end to permit access to said switchgear; a panel slidably mounted at each end of said enclosure for closing the opening therein; and a panel slidably mounted at said top and, in closed position, overlying said end panels thereby preventing opening thereof until it is slid in one direction to uncover one end panel and in the opposite direction to uncover the other end panel.
 2. The combination according to claim 1 wherein stop means on said enclosure limit sliding movement of said top panel in opposite directions.
 3. The combination according to claim 2 wherein locking means on said enclosure prevent movement of said top panel in either direction from said closed position.
 4. The combination according to claim 3 wherein said locking means includes: an inverted T-shaped locking bar depending inside said enclosure from said top panel and having an opening intermediate the ends of its crossbar portion registering with an opening in a sidewall of said enclosure when said top panel occupies its closed position; and a locking member pivoted on said sidewall and having a tongue for extending through said registering openings; and the parts of said crossbar portion at the ends of said opening therein overlying said opening in said sidewall when said top panel is moved away from its closed position thereby preventing insertion of said tongue in said opening in said crossbar portion.
 5. The combination according to claim 1 wherein: a drawer is slidably mounted on said enclosure for movement out of one end thereof and carries part of said switchgear; and locking means on said enclosure prevent withdrawal of said drawer.
 6. The combination according to claim 5 wherein said locking means underlies said top panel in its closed position and is accessible only when said top panel is moved in one direction away from its closed position.
 7. The combination according to claim 1 wherein: an outstanding flange borders said opening at each end; and guide means at the lower end of each of said openings hold the respective end panel against the respective flange.
 8. The combination according to claim 7 wherein said guide means has an inclined surface for engaging the lower end of a vertical flange along the respective side of each end panel.
 9. The combination according to claim 7 wherein stop means at the top of each end panel engage the respective flange and limit the extent of downward travel thereof.
 10. The combination according to claim 1 wherein antifriction means along the upper edges of the sidewalls of said enclosure support said top panel and facilitate sliding movement thereof.
 11. The combination according to claim 10 wherein each antifriction means includes: a support bar carried by the respective sidewall of said enclosure; and a ball on said support bar engaging the underside of said top panel.
 12. The combination according to claim 1 wherein a mechanical maze construction is located along the edges of said panels to reduce the likelihood of entrance into said enclosure of small cross section, tools, wire and the like.
 13. The combination according to claim 12 wherein said mechanical maze comprises interfitting flange means on said panels and said enclosure. 